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Skin Concept

Transepidermal Water Loss (TEWL)

The natural evaporation of water out through the skin's surface — when it's too high, skin feels dry and tight regardless of how much you moisturize.

What it does

Understanding TEWL helps explain why some skin stays dry even with heavy moisturizer use — and why barrier-supporting and occlusive ingredients matter more than simply adding more hydration.

Glow notes

Transepidermal water loss (TEWL) refers to the passive evaporation of water through the skin's outer layers into the surrounding environment. It happens continuously — it's a normal part of skin physiology — but when the skin barrier is compromised, TEWL increases significantly, meaning the skin loses moisture faster than it can absorb or retain it. This is why some people experience skin that feels persistently dry or tight even after applying thick moisturizers: they're adding water-attracting ingredients, but the damaged barrier can't hold that moisture in place. The water evaporates out before it can benefit the skin. Reducing TEWL requires strengthening and sealing the barrier. This is the job of occlusive ingredients (like Marula Oil), emollients (squalane, jojoba), and barrier actives (ceramides, ectoin, niacinamide). It's also why the order of your routine matters: applying humectants on damp skin and immediately sealing with an emollient is one of the most practical strategies for reducing TEWL in a home routine.

Skin goals

Barrier Support Hydration Dry Skin Routine Basics Sensitivity

Routine note

If skin feels persistently dry despite moisturizing, focus on the Seal step (Marula Oil) and barrier actives (Milky Drops, Bounce) rather than adding more moisturizer.
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